Valve for percussive tools.



O. H. PECK.

VALVBTQR PERGUSSIVE TOOLS.

APPLICATION'TILED MAY 28, 1913.

Patented. Mar. 10, 1914,

curan s'rnras PATENT OFFICE.

CAII) H. PECK, OF ATHENS, PENNSYLVANIA, ASSIGNOR 'lO-INGERSOLL RAND COM-PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION F NEW JERSEY.

VALVE FOR PERCUSSI'l-TE TOOLS.

Losoaee.

Patented Maf. 10, 1914..

Application filed May 28, 1913. Serial No. 770,296.'

The object of this invention is to producegy a toolwhich will be of higheliiciency in opeA erationand, at the same time, consume a '.15comparatively small quantity of the operating luid.A .y

With this object in View, 1 have devised a tool a practical'embodimentof which.y is

shown in the accompanying drawings` in 2o which-1- Figure 1 shows alongitudinal section thrangh the tool, Fig. 2 shows a slmilaresectio/j'chest and a portion of the cylinder and Fig.

Syshows a transverse section taken -\on` the. i line III- III of Fig.'2.

The tool is shown' as a riveting'hanimer comprising a cylinder-g1 inwhich reciprocates a piston 2 which strikes on` the rivet set 3. To theother end of the cylinder, from the rivet set, is attached the 4usualhandle 4, y

actuating fluid being admitted..,thre,th1-ough tothe inlet passage 5. Onthe upper side of the toolis a valve chest 6 having a, generally,cylindrical bore into the rear end of which is fitted the rear end 7 of'a valve supporting plug 8 the forward part of which i.;

i et yside y thereof.

of smaller dlametervthan the part 7 and projects v through the valvechest to the other From the forward end of the leads to the c linder alar e fluid essa e 9 y g p 'g lug 8j A face of the valvesupportingplurality of passages 10 lead t rough the plug from the passagek)opening into the valve chest at two points, the exhaust ports 11 andinlet ports 12. The other end of the valve plug is provided Iwith alarge inlet ychamber 13 whichl communicates with the inlet passa e5.'From the forward end of this inlet c amber, which is of smaller d1`amet'er, inlet ports 14, for the rear end'of the. cylinder, open into'the valve chest.

y v dlightlyifarther forward, the;v valve plug is a liameter forming aflange 15 to iphery of which very small pas-v Ward on ,a larger scalethrough the valveI sages 16 lead from the chamber 13. From the valvechest and so placed as to register v'with the inlet ports 14, an annularinlet port 17 leads into the cylinder. Farther along the valve chest andfarther from the rear end of the cylinder, an annular exhaust port 18opens into the cylinder, while slightly forward of the annular exhaustport 18 and separated therefrom by a'shoulder' 519, is an exhaust port20opening to the atmosphere through a plurality of passages 21. Slidingin the valve chest on the supporting plug 8, is a valve 22, the forwardportion of which controls the exhaust of the tool and the rear portionof which, which is of larger diameter, controls the inlet to the tool.Through the forward part of the valve are ports 23 adapted to connect'the exhaust ports/ 1 1 and the .atmospheric exhaust port 20 when thevvalve is 1n its forosition. Just to the rear of these ports 1s aflange, 24 adapted to co-act with the shoulder 19 and close o the port18.

i, from the port 2O when the valve is in its forward position but whichallows the fluid to passfrom the port 18 to the port 2O when the valveis in ,its rearward position, the' ports 23 at such a time being outofregister with the ports'll. `On, the inside ofthe rear portion of thevalve is a slight depression 25 which allows communication between therestricted 'passa es 16 and the inlet ports 12 whenA the va ve is in itsrearward position. When the valve is in its forward position its rear\end uncovers the ports/14 and allowscommunication between them and theport 17. For the operation of the valve three surfaces of thevalve comeinto effect, one consisting of the forward end' of the valve 26 whichalone serves `,to drive the valve rearwardly. `From this face of them,valve the passage 27 leads to a port 28 in the cylinder, slightlyforward of its .central point. To this face also leads a passage 29 fromthe forward end of the inlet chamber 13. Opposed to this surface 26 aretwo smaller surfaces which serve to operate the valve' in the otherdirection. One of these is the surface 30 which is'alwa s open throughthe ports 12 to the front en of the cylinder yand the other is the rearsurface of the valve 15 which is made up of two surfaces, one the rearsurface of a flange on the valve and the other the surface 32 of therear end of the valve. This surface is only all efectiva 110 when thcvalve is in its rearward position and the outer 'surface of fiange 31 isin contact with the shoulder 33 on the side of the valve chest, as willbe seen later. The total arear of these surfaces is greater than that ofthe surface 26. From the inlet chamber 13 a small leak port 31 leads tothe inlet port 17 so that it is at all .times in communication with thecylinder' while from the inlet chamber 13 a small leak port 35 leadsinto the extreme end of the cylinder, these two leak ports being forlpurposes which will later appear.

In operation, supposing the parts to be in the position shown in Fig. 1the valve 15 having just been thrown rearwardly, air will enter thefront end 0f the cylinder through the inlet chamber 13, restrictedpassages 16, ports 12 and passages 10 and 9 driving the piston to therear. A very small amount of air is needed for this purpose as therecoil of the piston from the tool has a large ,effect in driving itback. As the piston moves rearwardly into the cylinder, air from theback end, is exhausted through the port 18 and port 20 and `passages 21to the atmosphere. It will be noticed that for a short portion of thestroke of the piston, until the rear end of it passes the port 28, theair can escape from the surface QG through the passage 27 to thecylinder which is at atmospheric pressure, or ne'arly so, on account ofthe fact that the exhaust port 18 is open to atmosphere. Sufficient airhowever will be taken from the chamber 13 through the passage 29 toprevent the pressure of the surface 30 from throwing the valve forwardlyagain. Then in its rearward travel the rear end of the piston coversthe' exhaust port 18 its rear end will have uncovered the port 28 andthe same, 0r approximately the same, pressure will therefore be exertedagainst the surface 26 and the surface 30. As the piston moves past theport 18 it will trap a certain amount of air in the back of thecylinder, which will be compressed as the piston moves farther towardthe end of the cylinder. This compression will be increased materiallyby the leakage of live fluid through the ports 34 and This pressure willbe directly exerted on the surfaces 31 and and will, after the pistonhas traveled a short distance past the port 18, be sufficient toovercome the compression on the part of surface QG which is not balancedby the ressure on the surface 30. This will move t e valveforwardopening communication between the inlet ports 14 and 17 and between theexhaust ports 11 and 20. By reason of the size of passage 9 and theexhaust ports 11`and 20 a veryfree exhaust is permitted from the frontend of the tool.

Fluid will thus be admitted into the rearI end of thecylinder drivingthe piston again forward. 'As the piston moves forwardly,

at first the only pressure on-the mlve is on the surface 3Q, pressureon' the` rear surface of the flange 31 being counterbalanced by that onthe forward surface, as the liange 31 is now out of contact with theshoulder 33. As thc front end of thelipiston passes the port 28 theescape of fluid passing through passage Q9 is prevented and pressurebegins to build up against the surface :26. This is not sullicient tomove the valve back, however, until the rear end of the pister. uncoversthe port,.28 allowing the full -live pressure in the cylinder to passthrough the passage QT'against the surface 2G. is then thrown rearwardlyand the cycle, above described, repeated,

It will be seen from the above description that the air driving thepiston has free access to the cylinder to drive it forward and is notcut off until practically the forward end of the stroke. The largeexhaust passages from the front end at the same time allow the air fromin front of the piston to escape freely, the result being a heavyuncushioned blow by the pistonon the rivet set. By'reason of therestricted area 0f the inlet assages 1G for the forward end of the cyliner` a very small amount of air is admitted to' the cylinder on therearward stroke of the piston, the return being accomplished largely bythe recoil of the piston. The air used in the tool is largely ex )endedtherefore on the effective stroke of t e pis,- ton the result being atool of high efficiency and economy for the purpose.

It is to be understood. that the present showing and descriptiondiscloses only one specified modication of my invention and other formsand modifications are included in the spirit and scope of the inventionas expressed in the claims.

Y 'lVhat I claim is: r

1. In a percussive tool, a cylinder, its piston, a valve chest, inletand exhaust passages for-the rear end of the cylinder, a fluid passageextending rearwardly of the cylinder from the "forward end of thecylinder to said valvechest, a valve supporting stem extendingrearwardly from" said forward passage, said stem having exhaust andinlet ports therein communicating with said forward passage, an exhaustopening in said valve chest, an inlet passage and a valve sliding onsaid valve supporting stem and adapted to alternately connect saidexhaust ports and passages and said inlet ports and passages.

2. In a percussive tool, a cylinder, its piston, a valve chest, inletand exhaust passages for the rear end of thc cylinder, a fluid passageof large area extending rearwardly of the cylinder from the forwardend-of the cylinder to said valve'. chest, a valve supporting stemextending rearwardly` from said large passage` said stem having exhaustThe valve and inlet ports-therein communicating with said large passage,an exhaust opening of large 'area in saidvalve chest,ian inlet passageof very constricted area, and a valve sliding on said valve-supportingstem .and

adapted to alternately connect said exhaust ports and ,passages and'saidinlet ports and passages. 'l

. opening from saidjvalve' chest 'to the rear -end of the cylinder,.apassage oflarge areaA streted'area for the front end and an inletl -3.`In a percussive tool,-a.cylinder, its-piston, a valve chest, inlet andexhaust ports extendingrearwardly of the cylinder to'said l l valvechest,'a valve supporting plugin said vl5.

valve chest having inlet 'and exhaust ports opening from said vlargepassage to said4 valve chest, and an inlet passage of con! passagefor/the back end opening from the inlet of the tool to said valve chest,an at niospheric exhaust from said valve chest,-

' and a valve sliding on said valve plug,

adapted to connect said valve plug exhaust with said atmosphericexhaust, and 'said rear end valveplug inlet with said rear end cylinderinlet, and in its other position to connect said rear end cylinderexhaust vwith said atn'iospheric exhaust and said constricted valve pluginlet passage with said valveplug inlet port. v v

4.. In a percussive tool, a cylinder, its piston, inlet and exhaustpassages for both l ends of the-cylinder, the inlet port for one endbeing constricted in area, and the exi live vfluid pressure, while attheend of the .l v

haust port for the other en d lacing at a distance rom the end-of thecylinder, a valve for controlling said passages having a sur# face foroperating it in one direction and A.other stroke, said first surfaceand' the other of said smaller surfaces will be exposed to live pressurelessened .by said constricted passage andthe 4lirst of said smallersui'- faces will be exposed to piston compression. 5. In a percussivetool, a'cyhnder, its

piston, inlet andexhaust ports communicating Vwith the forward end ofthe cylinder, an inletV port for therear end 'of the. cylinder, a-nexhaust-port farther from the n 're'ar end of the cylinder than saidinlet port and a valve'foi' controllingxsaid ports, having a surfacefor operatingit 1n one direction and two smaller surfaces of a totalarea greater-than said first surface for Operating the valve in theother direction, one of said smaller surfaces communicatingwitheachye'nd ofthe cylinder, a passage leading frein the cylinder to saidfirst surface and so placed as to be uncovered by the piston near`theend of each stroke, so" that at the end of the forward sti'oke the firstsurface and one of the smaller surfaces will be exposed to livepressure, While at the end of the rearward stroke, the first surface andone of the smaller surfaces will he exposed lo live prcssureand theother Smaller surface willfbe exposed to the pressure ofthe fluidtrapped hy the piston in the rear end of the cylinder.

6. In a percussive tool, acylinder, its pis ton, inlet andexhaust'passages for both ends of the cylinder, avalve 'for-controllingsaid passages having a surface for operating said valve in one directionand two smaller sur-v faces of greater total area than said firstsurface for operating the valve in the other direction, and passages soarranged that lluid pressure will be exerted on said first surface andone of said smaller surfaces at one end of the piston stroke and on allsaid surfaces atA the otherendof the piston stroke.

In testimony whereof, Ivhave hereunto set i my hand.

.CAIDIL PECK. lVitnesses :v

' J. I.IIANG`ELAND, IVM/run S, Prox.

